myopia:the role of cone opsin mutations & glasses that control axial elongation

Conditions: Myopia

Summary: 1. to determine the effect of spectacles with a red blocking filter on myopia progression in children. 2. to determine the effect of spectacles with a holographic diffuser that spreads incident light rays over an angle of 0.5 degrees on myopia progression in children 3. to determine the combined effects of spectacles with a red blocking filter and a diffuser that spreads incident light over an angle of 0.5 degrees on myopia progression in children.

in this clinical trial we will determine whether commercially available lens tints that are normally used for cosmetic purposes or for blocking sunlight have a beneficial effect of slowing axial eye growth in children with myopia when used alone or in conjunction with a holographic diffuser that blurs the image slightly. the following procedures will be performed on a total of 240 children from 8 to 13 years of age: 1. color vision tests (richmond hardy-rand-rittler pseudoisochromatic plate test and/or the rayleigh match test and/or the neitz test of color vision), and machine-based vision tests using the titmus tester (color vision, binocularity, acuity, and heterophoria tests); 2. each subject will provide a blood sample or a buccal swab for genetic analysis of the long and middle wavelength cone photopigment genes in order to determine the relationship between the cone opsins and myopia; 3. eye measurements including axial length and corneal curvature will be performed using the zeiss intraocular lens master; 4. cycloplegic autorefraction will be doe at the beginning of the study before participants start wearing the study spectacles, after 18 months if wearing the study spectacles, and 6 months after participants stop wearing the study spectacles. 4) subjects will be randomly assigned to one of four groups, consisting of 60 subjects each, each group will be assigned one of four study spectacles. the study spectacles for all participants will have the optimal lens corrections for both eyes. group 1 participants will wear spectacles with lenses tinted to blocks red light. group 2 participants will wear spectacles with lenses that have a holographic diffuser on surface of and that are tinted to reduce the light intensity by the same amount that the red-blocking tint does. group 3 participants will wear spectacles that are tinted to block red light and that have a holographic diffuser. group 4 participants will wear spectacles that are tinted to reduces the light intensity by the same amount that the red-blocking tint does. participants will wear the study glasses for 18 months. axial length measurements will be taken twice prior to when subjects begin wearing the glasses and once every three month thereafter.

Eligibility criteria:
inclusion criteria: * nearsighted having a refractive error of at least -0.5 diopters * myopia progression at least -.50 d per year in previous year * astigmatism and anisometropia not more than 1.5 d * distance monocular acuity 6/6 or better * near monocular acuity of 0.4 m or better * stereoacuity not more than 40 sec of arc at 40 cm * able to respond to subjective testing * no contact lens use during the study * able to comply with wearing the experimental lenses daily for 18 months * able to have axial length measurements accurately on the zeiss intraocular lens master * willing to donate a blood sample or a buccal swab for genetic analysis * can be refracted to 20/20 or 20/15 exclusion criteria: * glaucoma, amblyopia, strabismus * ocular disease * developmental delay * history of wearing bifocal lenses * any type of eye surgery * color vision deficiency

Keywords: myopia nearsightedness axial elongation of the eye refractive error